CN102380613B - Preparation method of powder-metallurgy refrigeration compressor valve sheet - Google Patents
Preparation method of powder-metallurgy refrigeration compressor valve sheet Download PDFInfo
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Abstract
The invention relates to a preparation method of a powder-metallurgy refrigeration compressor valve sheet. The preparation method is characterized by comprising the following steps of: mixing iron powder, high-alloy main powder, graphite powder, manganese sulfide powder and zinc stearate powder according to certain proportion, leading the weight percentage of all elements in the total components to be as follows: 0.5-2.0% of carbon, 3.0-6.5% of cobalt, 2.5-4.5% of chromium, 2.5-4.5% of molybdenum, 0.5-2.0% of nickel, 0.2-1.0% of vanadium, less than 3% of impurities and the balance of iron; using a mold to press and form the mixture to obtain a powder-metallurgy green blank; putting the green blank in a sintering furnace to sinter for more than 5 minutes with the sintering temperature being 1150-1250 DEG C; carrying out repressing and finishing on the sintered blank; carrying out quenching and annealing under the protective atmosphere; and carrying out grinding on the valve sheet. In the preparation method, the problems of the adding mode and effective alloying of the powder-metallurgy high alloy are solved, and higher forming density needed by the powder-metallurgy valve sheet material under higher alloy content is realized, so that the powder-metallurgy refrigeration compressor valve sheet achieves the needed wear resistance. The prepared powder-metallurgy refrigeration compressor valve sheet has the advantages of low material cost, high material utilization ratio and suitability for large-batch production.
Description
Technical field
The present invention relates to a kind of preparation method of powder metallurgy refrigeration compressor valve block, be applied to rotary air conditioner refrigerating compressor field.
Background technology
In the refrigeration compressor industry, domestic rotary compressor of air conditioner all adopts common high-speed steel material at present, or the stainless steel material is by mach valve block.Compare with the powder metallurgy compressor valve block, the valve block process velocity that common high-speed steel material or the machined of stainless steel material are made is slower, stock utilization is not high, and powder metallurgical technique is made compressor valve plate, stock utilization height not only, and be suitable for producing in enormous quantities, but compressor producer before using, assembling needs the powder metallurgy valve block is finish grinded processing on a small quantity.
The powder metallurgy compressor valve plate material is compared with the ordinary powder metallurgical material, needs to add certain alloying component, by the effective alloying in sintering process, and forms uniform hard point in tissue, improves the wearability of material.Therefore, selecting suitable material prescription, and improve the density of valve block and effective alloying of material under the prerequisite of high alloy composition, is the important technology difficult point that the present invention solves.Generally speaking, the density of powdered metallurgical material and alloy content are the two big factors that guarantee the product wearability; Usually the alloy adding method that adopts is not only unfavorable for improving shaping density and reducing the shaping die wear, and high alloy content requires also very strict for sintering condition.Higher alloy content is very big for the influence of the density more than the 6.8g/cm3 that realizes the powder metallurgy valve block.Selecting the technology of the suitable heavy alloyed addition manner of powdered metallurgical material composition, powder metallurgy and effective alloying, is to realize adopting powder metallurgical technique to make the key of refrigeration compressor valve block.
Effective adding method of sintered alloy can reduce the powdered metal parts forming pressure, reduces the mould loss, improve shaping density, and by the sufficient alloying of sintering process realization material, improve the wearability of material, be two key issues that the present invention mainly solves.
Summary of the invention
Technical problem to be solved by this invention is to make and the powder metallurgical technique state of the art at above-mentioned rotary air conditioner refrigerating compressor valve plate, and the preparation method of the lower powder metallurgy refrigeration compressor valve block of a kind of production efficiency height, the manufacturing cost that provide.
The present invention solves the problems of the technologies described above the technical scheme that adopts: a kind of preparation method of powder metallurgy refrigeration compressor valve block is characterized in that may further comprise the steps successively:
(1) the female powder of iron powder, high alloy, graphite powder, sulfuration manganese powder and stearic acid zinc powder are pressed stated mass ratio and mix, make the quality percentage composition of each element in total component be: carbon 0.5～2.0%, cobalt 3.0～6.5%, chromium 2.5～4.5%; Molybdenum 2.5～4.5%, nickel 0.5～2.0%, vanadium 0.2～1.0% is no more than 3% inevitable impurity, and surplus is iron;
Iron powder surplus: the female powder 20～24% of high alloy: graphite powder 0.6～0.8%: sulfuration manganese powder 0.4～0.6%: stearic acid zinc powder 0.65～0.75%; Iron powder surplus implication is exactly the content that 100% mass percent that deducts other component obtains.
(2) use the mould press forming to obtain the powder metallurgy green compact, shaping density is greater than 6.9g/cm
3
(3) place sintering furnace to carry out sintering on the powder metallurgy green compact, sintering temperature be 1150～1250 ℃ of times greater than 5 minutes, sintered blank density is greater than 6.8g/cm
3
(4) sintered blank is carried out multiple pressure finishing;
(5) under protective atmosphere, quench and tempering;
(6) valve block is carried out grinding, reach the final size requirement.
As preferably, the iron powder in the described step (1) adopts the high-purity atomized iron powder, and carbon content is less than 0.02% in this atomized iron powder, oxygen content is less than 0.25%, and silicone content is less than 0.05%, and phosphorus content is less than 0.02%, sulfur content is less than 0.02%, suppression performance under 600Mpa greater than 7.1g/cm
3, apparent density is greater than 2.9g/cm
3, acid is not melted less than thing 0.5g.
As improvement, the mould in the described step (2) adopts carbide alloy former and high-speed steel stamping.
Improve, described step (3) is to carry out under protective atmosphere again, and protective atmosphere is common heat absorptivity atmosphere or nitrogen-based atmosphere or vacuum, and described sintering furnace is meshbeltfurnace, push rod furnace, bell jar stove or vacuum drying oven.
Preferably, the protective atmosphere in the described step (5) refers to the nitrogen atmosphere that 0.2Torr is following, and temperature is 570～590 ℃, and 80～100 minutes time, tempering is twice.
At last, common plane grinding machine or double face abrading machine are adopted in the grinding in the described step (6).
Obtained a kind of powder metallurgy valve plate material of the present invention, its material prescription is: the quality percentage composition of each element in total component is: carbon 0.5～2.0%, cobalt 3.0～6.5%, chromium 2.5～4.5%; Molybdenum 2.5～4.5%, nickel 0.5～2.0%, vanadium 0.2～1.0% is no more than 3% inevitable impurity, and surplus is iron.
Compared with prior art, the invention has the advantages that: the means that adopt the female powder of high alloy to add obtain high alloy material, and dusty material has good suppression performance, simultaneously generally need not special sintering atmosphere, be suitable for economical mass production; The invention solves the heavy alloyed addition manner of powder metallurgy and effective alloying problem, realized higher shaping density under the required higher alloy content of powder metallurgy valve plate material, make the powder metallurgy compressor valve block reach required anti-wear performance; For requiring high alloy, highdensity sintered metal product, do not need too high forming pressure and special sintering condition, the simple and easy operating of whole technical process.Make rotary air conditioner refrigerating compressor valve plate with existing high-speed steel material or the machined of stainless steel material and compare, this powdered metallurgical material and manufacturing process have higher production continuity, and the stock utilization height, are suitable for producing in enormous quantities, reduce cost.
Description of drawings
Fig. 1 is rotary air conditioner refrigerating compressor valve plate part drawing;
Fig. 2 is powder metallurgy refrigeration compressor valve block shaping schematic diagram;
Fig. 3 is powder metallurgy refrigeration compressor valve block metallographic structure photo.
The specific embodiment
Describe in further detail below in conjunction with the present invention of accompanying drawing embodiment.
A kind of powder metallurgy refrigeration compressor valve block manufacture method in turn includes the following steps:
1, (iron powder is surplus: the female powder 20～24% of high alloy: graphite powder 0.6～0.8%: sulfuration manganese powder 0.4～0.6%: stearic acid zinc powder 0.65～0.75%) mix by a certain percentage with iron powder, the female powder of high alloy, graphite powder, sulfuration manganese powder and stearic acid zinc powder, make the percentage composition of each element in total component be: carbon 0.5～2.0%, cobalt 3.0～6.5%, chromium 2.5～4.5%; Molybdenum 2.5～4.5%, nickel 0.5～2.0%, vanadium 0.2～1.0% is no more than 3% inevitable impurity, and surplus is iron.
2, with the valve plate material powder that mixes, by shaping schematic diagram mode shown in Figure 2, press forming obtains powder metallurgy valve block green compact in the mould of design at the automatic forming press, and the shaping density of green compact is greater than 6.9g/cm
3
3, the powder metallurgy valve block green compact with press forming neatly are emitted in the sintering boat, and the sintering boat are placed on the guipure of continuous fritting furnace, or the sintering boat directly placed carry out sintering in clock-type sintering furnace or the vacuum sintering furnace.Sintering temperature is 1150～1250 ℃, sintering atmosphere is normal heat absorptivity atmosphere or nitrogen-based atmosphere or vacuum, sintering time was greater than 5 minutes, sintering furnace is meshbeltfurnace or push rod furnace or bell jar stove or vacuum drying oven, the sintering hardness of powder metallurgy valve block is more than the HRB90, and Fig. 3 is seen in the metallographic structure of material behind the sintering.
4, sintering finishes back taking-up powder metallurgy valve block sintered blank and carries out multiple pressure finishing, press finishing again on the shaping press, carry out full shaping in shaping mould, to correct the distortion of the powder metallurgy valve block sintered blank that causes because of sintering, the density of the powder metallurgy valve block after shaping is 6.85g/cm
3More than, the hardness of valve block is more than the HRB90.
5, after finishing, the powder metallurgy valve block quenches in protective atmosphere and tempering; Tempering is heated to 570～590 ℃ of insulations cooling after 90 minutes, twice of tempering in nitrogen atmosphere.
6, by rotary air conditioner refrigerating compressor valve plate drawing, accurate grinding is carried out on two planes of valve block.
Described iron powder adopts the high-purity atomized iron powder, and concrete chemical composition and performance see Table 1,2.
The chemical composition (%) of table 1 high-purity atomized iron powder
| The iron powder specification | Manganese content | Carbon content | Silicone content | Phosphorus content | Oxygen content | Sulfur content | Iron content |
| AHC100.29 | ＜0.01 | ＜0.10 | 99.5 | ||||
| ATOMET 1001 | 0.20 | 0.003 | - | - | 0.08 | 0.009 | ＞99 |
| 300M | 0.10-0.30 | ＜0.02 | ＜0.05 | ＜0.020 | ＜0.25 | ＜0.020 | Surplus |
Other performances of table 2 high-purity atomized iron powder
Wherein high-purity atomized iron powder AHC100.29 is produced by the Hoganas company of Sweden and He Genasi (China) Co., Ltd, and ATOMET 1001 is produced by Canadian QMP company, and 300M is that the Kobe Steel Ltd by Japan produces.
It is powder that the female powder of special high alloy adopts Fe-Co-Cr-Mo-Ni-V, and chemical composition sees Table 3:
The female efflorescence composition (%) of table 3 high alloy
| Iron | Cobalt | Chromium | Molybdenum | Nickel | Vanadium | Carbon | Other |
| All the other | 20-22 | 14-18 | 14-18 | 5-8 | 0.6-2.0 | 0.2-2.5 | ＜2 |
The apparent density of the female powder of special high alloy is 3.58g/cm
3, size distribution sees Table 4:
The female powder degree distribution of table 4 high alloy (%)
Mixed powder metallurgy refrigeration compressor valve plate material chemical composition reaches shown in the table 5:
Table 5 powder metallurgy refrigeration compressor valve plate material chemical composition (%)
| Iron | Carbon | Cobalt | Chromium | Molybdenum | Nickel | Vanadium | Other |
| All the other | 0.5-2.0 | 3.0-6.5 | 2.5-4.5 | 2.5-4.5 | 0.5-2.0 | 0.2-1.0 | ＜3 |
Claims (6)
1. the preparation method of a powder metallurgy refrigeration compressor valve block is characterized in that may further comprise the steps successively:
(1) iron powder, the female powder of high alloy, graphite powder, sulfuration manganese powder and zinc stearate powder are mixed by following mass ratio, make the quality percentage composition of each element in total component be: carbon 0.5～2.0%, cobalt 3.0～6.5%, chromium 2.5～4.5%; Molybdenum 2.5～4.5%, nickel 0.5～2.0%, vanadium 0.2～1.0% is no more than 3% inevitable impurity, and surplus is iron;
The mixing match of material is pressed:
The iron powder surplus, the female powder 20～24% of high alloy, graphite powder 0.6～0.8%, sulfuration manganese powder 0.4～0.6%, stearic acid zinc powder 0.65～0.75%;
It is powder that the female powder of described high alloy is selected special Fe-Co-Cr-Mo-Ni-V for use, wherein the percentage composition of each element in total component is: cobalt 20～22%, chromium 14～18%, molybdenum 14～18%, nickel 5～8%, vanadium 0.6～2.0%, carbon 0.2～2.5%, be no more than 2% inevitable impurity, surplus is iron; Apparent density is greater than 3.5g/cm
3
(2) use the mould press forming to obtain the powder metallurgy green compact, shaping density is greater than 6.9g/cm
3
(3) green compact are placed sintering furnace carry out sintering, sintering temperature is 1150～1250 ℃, and the time, sintered blank density was greater than 6.8g/cm greater than 5 minutes
3
(4) sintered blank is carried out multiple pressure finishing;
(5) under protective atmosphere, quench and tempering;
(6) valve block is carried out grinding, reach the final size requirement.
2. preparation method according to claim 1, it is characterized in that the iron powder in the described step (1) adopts the high-purity atomized iron powder, purity is greater than 99%, carbon content is less than 0.02% in this atomized iron powder, oxygen content is less than 0.25%, and silicone content is less than 0.05%, and phosphorus content is less than 0.02%, sulfur content is less than 0.02%, suppression performance under 600Mpa greater than 7.1g/cm
3, apparent density is greater than 2.9g/cm
3
3. preparation method according to claim 1 is characterized in that the mould in the described step (2) adopts carbide alloy former and high-speed steel stamping.
4. preparation method according to claim 1 is characterized in that described step (3) is to carry out under protective atmosphere, and protective atmosphere is common heat absorptivity atmosphere or nitrogen-based atmosphere or vacuum, and described sintering furnace is meshbeltfurnace, push rod furnace, bell jar stove or vacuum drying oven.
5. preparation method according to claim 1 is characterized in that the protective atmosphere in the described step (5) refers to the nitrogen atmosphere that 0.2Torr is following, and temperature is 570～590 ℃, and 80～100 minutes time, tempering is twice.
6. preparation method according to claim 1 is characterized in that common plane grinding machine or double face abrading machine are adopted in the grinding in the described step (6).
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